Installing Guest Additions on Debian Ubuntu Mint etc.

virtualbox_prereq_guest_additions.md

Installing Guest Additions on Debian

Follow these steps to install the Guest Additions on your Debian virtual machine:

sudo -i
apt-get update && apt-get upgrade
apt-get install build-essential module-assistant
# Configure your system for building kernel modules by running:
m-a prepare

Click on Insert Guest Addition CD image from the VM's Devices menu, then:

• server/no-gui: mount /media/cdrom (or check with lsblk the device name, mkdir /mnt/cdrom and mount it there)
• gui: the CD is usually automounted, df will reveal the path

Run the script (toujours root):

sh /media/cdrom/VBoxLinuxAdditions.run  

and follow the instructions on screen.

Possible Failures

DKMS module compliation fails

And the error message sends you to some file under /var/log AFAIR, that isn't of any help.
On one VM there was a mismatch between the kernel version (uname -r) and the directory names in 2 places:

• under /lib/modules/${kernel_version}
• under /usr/src/{kernel_version}

This was apparent as the symlinks in /lib/modules were broken (ls --color paints them in red). I manually created the missing symlinks, leaving the bad ones in place.